Ballast resistor questions on a '68 F100

[CN Spots]

Auto-electrical is not my bag, so bare with me...

I have a '68 Ranger with a 390, just rebuilt the engine, ready to fire. It has a Crane electrical conversion in the dizzy. The coil had a ballast resistor on it but another forum stated that I no longer needed it since I no longer have points. Is this true? I'd hate to torch it.

Also, the wire leading to the coil from the dash is brittle and cracking. I was going to replace it with another wire of similar gauge but Ford regards this as a "Ballast Resistor Wire"??? I didn't think Ford used those in the '60s. Does this wire truly provide resistance or is that just what they called the wire since it formally went to a ballast resistor? It's bundled with the temp and oil pressure sending unit wires. Thanks.

spots

 

[MikDee]

Re: Ballast resistor questions on a '68 F100

Yes, chances are that wire is the ballast resistor, unless you have a visible ballast resistor somewhere near the coil (if you know what one looks like?) If it's that wire, it does not deliver a full 12Volts with the key in the (on/run) position, originally to keep the points from burning up too quickly. You probably need a new switched (on/off/run) full 12Volts source (wire) from the ignition switch to power that Crane electronic ignition now.

An old style ballast resistor is a white ceramic looking block, with what looks like a coil of wire in the middle of it (a normal resistor)

 

[CN Spots]

Re: Ballast resistor questions on a '68 F100

I'm familiar with the ceramic type and there was one in the box of parts in the bed when I got the truck but there were also several other coils and brackets w/o ballasts. Hence my uncertainty. I'll try to call Crane this week and ask them if it matters. If I can get ahold of a human... that speaks English.

 

[Kenneth Brown]

Re: Ballast resistor questions on a '68 F100

For whatever its worth....... The truck DID come with a ballest resistor inline ie the wire and not a ceramic block. More for what its worth........ I ran a Mallory Unilite in my 67 SWB F100. It REQUIRED a resistor BUT the coil was to recieve a full 12+ volts. I said screw that and shot the ful 12 to my ignition also. The first module lasted about a week. The second lasted a little less. The third (and a new ceramic resistor) was still on the truck 7 years later after my brother sold it.

 

[seven up]

Re: Ballast resistor questions on a '68 F100

hello spots,

That is a great truck. The FE series of engines are teriffic. I agree that you should consult with crane on your specific application.

The installation guide could be online.

From my experience the "modules" in the distributor require a resistance to prevent burnout. The amount of resistance in "ohms" is the key. There are many many ballast resitors and coils with varying degrees of resistance.

Of course the varied systems out there each requires their respective installation procedure.


Enjoy

 

[ThumbPkr]

Re: Ballast resistor questions on a '68 F100

The Mopar ignition systems with a ballast resistor used a 6 volt coil and the ballast resistor was bypassed in the start circuit to zap the coil with the full 12 volts to start the engine.Once you released the key to the run position 6 volts was dropped across the ballast resistor to give the 6 volt coil the voltage that it expected.
None of this is big news I know but the point that I wanted to make is that you could buy a 12 volt coil as well if you had to eliminate the ballast resistor for any reason so that you did not burn up your ignition parts,especially the points were very sensitive to over voltage.Ron G

 

[rwise]

Re: Ballast resistor questions on a '68 F100

I went with MSD on me dodge, An oil cooled high output coil, and I use 2 different distributors, the OEM is in it now, and the MSD centrifugal advance is behind the seat (in case a Hemi wants to play I can drop it in) The wire that went to the resistor was (is) used to turn on the MSD and it gets its power directly from the battery! I also still have the OEM ignition on the truck and can be use as a backup by just unplugging one and hooking up the other!
Go by the manufacturers instructions they now there product
And yes the resistor (wire or block) is just to not burn the points while running.
I think there were some that also tapped the secondary side of the resister for 6 volts to other things

 

[CN Spots]

Re: Ballast resistor questions on a '68 F100

Crane said it HAD to have a resistor. I put one on and she fired right up.

The local Ford dealership actually found that wiring harness (start, temp,oil) still in stock in a dealership in Kentucky. Good news since no resto company makes one.


spots